Capacitors are limited by their dielectric constant. As a result, there is a constant search for dielectrics that have a high dielectric constant in order to make a smaller capacitor. In addition, it is common for the dielectric constant to vary with the voltage of the input signal. Generally, the dielectric constant is lower the higher the voltage of the input signal. As a result, it is also desirable to have a dielectric that has a dielectric constant that is essentially flat over a wide range on input voltages.
An important use of capacitors is for decoupling signals such as power and ground or input and output signals. The semiconductor industry requires numerous decoupling capacitors for each integrated circuit. Present decoupling capacitors are placed on circuit boards between leads off the integrated circuit. For high frequency circuits, the distance between the leads on the integrated circuit and the capacitor results in inductance that limits the effectiveness of the decoupling capacitor. In addition, the discrete capacitors used as the decoupling capacitors add cost and manufacturing complexity.
Thus there exists a need for an improved capacitor that may be used as a decoupling capacitor for integrated circuits.